Soil factors influencing the prevalence of tunga penetrans in Gaichanjiru location of Murang'a county, Kenya.

Abstract

The Tunga penetrans is an ectoparasite that embeds in the epidermis of its host and results into a disease referred to as tungiasis. This study aimed at investigating soil factors that influence off- host stages of Tpenetrans population and hence the prevalence of tungiasis. This was cross sectional study where sixty households were selected through simple random sampling technique from the area. All individuals in the selected homesteads were examined for presence of tungiasis related lesions. Tungiasis was manifested by presence of lesions of embedded T penetrans at different stages of development. Soil samples collected from the households were analyzed and examined for the presence of larval stages. Organic matter content of the soil was determined through loss by ignition method in a muffle furnace. Soil pH was determined using a pH standard probe meter. Soil moisture was determined by drying the soil in an oven. Size of granules was determined using sieves of specific sizes and an electromagnetic shaker machine. Color of the soil was established using munsell soil colour chart. Soil samples were also examined for the presence of larvae under a dissecting microscope. Out of 374 persons living in the sampled houses, 48.5% of these persons were infested with Tpenetrans. Of these 30% had severe infestations, 23% mildly infested and 47% had low infestations. Data were analyzed using analysis of variance (ANOVA), regression and Pearson correlation coefficients. Soil factors influenced the prevalence of tungiasis by up to 33% (P=0.001) and the T penetrans population by up to 39.7 % (P=O.OOO). Organic content had an insignificant relationship to tungiasis prevalence (P=O.179) and population (P=O.615). Soil texture was also found to have no relationship with T penetrans population (P=O.615) and prevalence of T penetrans (P=O.179). Soil colour also had no influence on prevalence of T penetrans infestations (P=O.553) and population T penetrans (P=O.660). The soil pH influenced the population of T penetrans (P=O.OOO) but not the prevalence of Tpenetrans infestations (P=O.532). The soil moisture also had an effect on Tpenetrans population (P=O.OOO) and not on the prevalence of tungiasis (P=O.063). Data from this study indicates that soil moisture and soil pH can be manipulated in order to serve as targets of control of tungiasis in addition to other control measures. These control measures would aim at interrupting the life cycle of T.penetrans by reducing larva population and subsequently the adult population leading to low infestation and hence reduced prevalence.